MINNEAPOLIS (WCCO) — Each Friday, Heather Brown answers some of our viewers’ questions that we didn’t get to during the rest of the week. This week, she’s learning about our nation’s birthday: the Fourth of July!

Who is Uncle Sam?

Samuel Wilson was a meat packer from upstate New York who supplied beef to the Army troops during the War of 1812. He would stamp all of his boxes with U.S., which stood for the United States. The troops, though, referred to the food as Uncle Sam’s. A newspaper later picked up the story and the character was made popular through political cartoons.

What actually happened on July 4, 1776?

Despite popular belief, the colonies declared their independence that day (which was actually July 2), July was the day the wording of the Declaration of Independence was finalized. It was that date put on the document.

How do fireworks get their colors?

Each firework is a package of chemicals. When heated, those different chemicals release different amounts of energy and it’s the energy that determines the color.

For example, red fireworks are made with strontium salts and blue ones are partly copper compounds. Purple ones are a combination of the two.